Photographic light control device



Nov. 1, 1949 c, ANDERSON 2,486,727

PHOTOGRAPHIC LIGHT CONTROL DEVICE Filed March 23, 1948 2 Sk'wets-Sheet 2 HUD. if p 45 1 E 22 /7 E I I I I I III III]! I L o L a 4 91A] q:

. 6 f7 BY 7 2 {7 J4 K ,INVENTOR. 17. 47 J2 f0 74 fie arm/r Cfirclemop Patented Nov. 1 1949 ulvrrro STATES PATENT OFFICE Beniamin C; Anderson, Kansas,City, Mo.

Application March 23, 1948, Serial No. 16,436

3 Claims. (Cl. 171-97) A main object of the invention i sto provide a novel and improved lamp control device for regulating the intensity oi illumination during photography, said device being very simple in construction, easy to. operate; and providing a considerable degree of variation of illumination although employing conventional photographic lamp bulbs as the source of illumination.

A further object of the invention is to provide an improved pneumatically-controlled lamp switching device for use in photography, said device providing different degrees of illumination as, required before and during the exposure of the photographic plate or negative, whereby the eifects of glare are minimized, lamp economy is obtained, and eflicient control of lighting conditions by the phdtographer is achieved.

Further objects and advantages of the invention will become apparent from the following description and claims, and from the accompanying drawings, wherein:

Figure 1 is a top plan view of a photographic lamp control device constructed in accordance "with the present invention.-

Figure 2 is a cross-sectional view taken on line 2--2 of Figure l.

Figure 3 is a cross-sectional view taken on line 9-4 of Figure 2. a

Figure 4 is a schematic wiring diagram illus trating the basic electrical connections of the iampcontrol device of Figure 1.

figure 5 is a schematic wiring diagram illu trating a modification of the wiring arrange-- ment of the device of Figure 1.

Figure 6 is a diagram similar to Figure 5, but illustrating the use of various lamp combinations in each of the circuits controlled by the device of the present invention.

Referring to the drawings, H designates a housing of generally rectangular shape, although other desired shapes may be employed within the spirit of the invention. Mounted in one end wall of housing ii is a conventional socket i2 oi the male type, and engaged therewith is a conventional female plug I3 connected to a line cord i4. Secured in the other walls of housing H are respective double female sockets l5, l6 and I1. One terminal of socket l2, indicated at i8 is connected by a wire I9 to one terminal of socket 15. The other terminal of socket I5 is connected by a wire 20 to one terminal of socket IS. The other 2 terminal of socket I8 is connected by a wire 2| to one terminal of socket II. The remaining terminal of socket I1 is connected by a wire 22 to the remaining terminal, indicated at 23, of socket l2.

Designated generally at 24 is a single-throw double-pole pneumatic switch, which comprises a cylindrical housing 25 having a flexible diaphragm 26 as its bottom wall and connected by a fitting 21 secured to its top wall to a flexible hose 28 having connected to its end a rubber bulb 29. Switch housing 25 is secured within housing I I by the fitting 21 which passes through the top wall 3| of housing H and is secured thereto by a nut 30. Secured to the top wall 3| of housing H by fitting 21 is an inverted U-shaped bracket member 32 which is interposed between switch housing 25 and said top wall 3| and has the vertical depending arms 33 and 34. Secured to arm 34 is a bracket element 35 formed with a bottom inwardly facing channel portion 36 having an inwardly projecting bottom arm 3'I.' The lower end of arm 34 is formed with a notch 38 through which arm 31 projects. Loosely received in channel portion 35 and in notch 38 is one end of an armature 39. Transversely secured to armature 39 is an insulating bac lli and bearing upwardly against bar 40 is the free end of a leaf spring BI secured at its other end to the upper portion of bracket element 35, whereby armature 39 is biased upwardly. Armature 39 is notched at each side at its intermediate portion, and is straddled at said notched intermediate portion by the lower centrally-notched portion of a vertical plate member 32. A disc member 83 is rigidly secured at its under side to the top end of vertical plate member 42 and bears against diaphragm 26. Disc 53 is movably positioned in a cylindrical cavity defined by an annular block 114 secured to housing it below diaphragm 26. Block 44 carries at its lower surface an annular stop disc 45, which limits downward movement of disc 43. Instead of employing disc 45 a suitable 'stop arm may be secured to bracket arm 33, said stop arm being arranged to underly the movable end of armature 39 so as to limit downward movement thereof. threaded through armature 39 and engageable with the bottom edge of plate member 42. Screw 42' is provided with a locknut 46. By means of screw 82' the plate member 42 may be elevated to a desired position of adjustment with respect to armature 39. When bulb 29 is compressed, diaphragm 26 will be flexed downwardly causing Designated at 42' is an adjustment screw.

armature 88 to be pivoted downwardly against the biasing force of spring 4|.

Secured 'to the .ends of bar 48 are respective switch arms 41 and 48. Secured to bracket arm 33 is an insulating plate member 48 carrying stationary contact strips 58 and 5| engageable by the respective switch arms 41 and 48 responsive to downward movement of armature 38, as above described. Contact strip 58 is connected by a wire 52 to wire I8 and contact strip 5i is connected by a wire 58 to wire 22. Switch arm 8? is connected by a wire 54 to wire and switch arm 48 is connected by a wire 55 to wire 26. Mounted in the top wall 3! of housing ii is a single-pole single-throw switch 56.

To facilitate discussion or the apparatus, an initial arrangement is illustrated in which the terminals of switch 56 are connected to the respective switch arms 41 and 48, as shown in Figure 4. Normally, with all switch contacts open,

the respective double sockets S5, IS and I? are connected in series to the line wires t9 and 82, as shown in Figure 4, whereby the lamps connected to said double sockets, shown at 51 in Figure 4, glow at uniform dimness.

With the parts in normal positions, as shown in Figure 4, if bulb 28 'is compressed, switch arms 41 and 48 engage the respective contact strips 58 and 5i. This connects wire 54 to wire 52 and wire 55 to wire 53. All of the double sockets l5, I6 and I1, are thus connected in parallel to the line wires I9 and 22, and the lamps glow with uniform maximum brilliance.

' Should it be desired to accomplish uniform dlmbright illumination control employing only the lamps in double sockets I5 and H as shown in Figure 4, the lamps in double socket [5 being removed, switch 58 can be closed to shunt double socket l6, thereby connecting double sockets I5 and I! in series with the line wires I8 and 22, and causing the lamps in double sockets I5 and I! to glow at uniform dimness. Here an undesirable condition arises however, in that if bulb 28 is compressed before switch 55 is opened, shortcirculting of the line wires will occur. To avoid this undesirable arrangement, to avoid the possibility of a short circuit, and to conveniently permit the desirable versatility arising from the option of using either three or two double sockets to accomplish uniform dim-bright illumination control over a greater number of lighting combinations, extra-stationary contacts may be provided, as shown at 58 and 58 in Figure 5, said contacts being carried by the insulating plate 48 above the respective contact elements 58 and 5|, the switch arms 41 and 48 being normally in respective contact therewith. To these extra contacts the terminals of switch 56 are preferably connected in lieu of switch arms 41 and 48. Under these conditions, when bulb 28 is compressed, the switch arms 41 and 48 will move downwardly out of engagement with contacts 58 and 58 and into engagement with contacts 58 and 5|, changing all three double sockets I5, I8 and H. from series energization to parallel energizatlon with switch 58 open, or changing sockets I5 and I1 (socket I5 being ignored on the assumption that it is not required) from series energizatlon to parallel energizatlon with switch 55 closed. This is all accomplished with no risk of short-circuiting the line wires even if either of switch arms 41 or 48 should fail to operate. Nor will a short circuit occur if switch 55 is accidentally not in the desired position, 4

Figure 6 illustrates an arrangement generally similar to Figure 5, except that parallel lamp circuits I5, I8 and H are connected in place of the double sockets I5, I5 and I1 0! the arrangement of Figure 5. The large circles represent bulbs of twice the wattage of those represented by the smaller circles. Said parallel lamp circuits may contain various balanced arrangements cl conventional lamps to provide diiferent degrees of illumination with uniform dim-bright control. Particularly diagrammed in Figure 6 are nine uniform dim-bright lighting combinations possible with conventional No. 1 and No. 2 photoflood lamps, each of which combinations can be safely carried by the average 15 ampere house circuit. The first four lighting arrangements in Figure 6 are accomplished with switch 58 closed and using only the sockets connected to the lamp circuits I5 and I1 (corresponding to the double sockets i5 and IT in Figure 5). As explained above in connection with Figure 5, switch arms 41 and 48 will normally be in contact with the respective upper contact elements 58 and 58. In this posi tion, with switch 55 closed, branch I5 is shunted out of the circuit, creating a series arrangement of branches I5 and I1. Thus uniform dimming is accomplished.

When bulb 28 is compressed, switch arms 41 and 48 move away from their normal contact with the respective upper contact elements 58 and 58, breaking the series arrangement, and move into engagement with respective contact elements 58 and 5I,. causing the branch circuits I5 and I1 to be connected in parallel to the line wires I8 and 22, and providing uniform maximum illumination.

The other five lighting arrangements in Figure 6 are accomplished with switch 55 open using lamp circuits I5, I 5 and I1 Under normal conditions, with switch 55 open, circuits I5, I6 and I1 will be connected in series with the line wires I8 and 22, the lamps thus burning at uniform dimness. When the bulb 29 is compressed, switch arms 41 and 48 move into engagement with respective contact elements 58 and 5|, causing the branch circuits I5, I5 and IT to be connected in parallel to the line wires I8 and 22 and providing. uniform maximum illumination.

Any combination of commercially available types of lamps which can be arranged in the proper balanced grouping of twos or threes may be employed with the means above described to obtain uniform dim-bright illumination control, and the number and size of the lamps employed will be limited only by the maximum current rat ing of the line wires and other conductors employed in the system.

While certain specific embodiments of an illumination control means for photography have been disclosed in the foregoing description, it will be understood that various modifications within the spirit of the invention may occur to those skilled in the art. Therefore, it is intended that no limitations be placed on the invention except as defined by the scope of the claims appended herewith.

What is claimed is:

1. A photographic illumination system comprising a first, a second and a third outlet socket, a two wire power line having one wire permanently connected to one side 0! said first socket and its other wire permanently connected to one side of said third socket, conductor means permanently connecting the other side of said first socket to one side of said second socket and conductor means permanently connecting the other 5 side of said third socket to the other side of said second socket to permanently connect said first, second and third sockets in series with said line wires, and manually operated means for tem-' nently connected to one side of said first socket and its other wire permanently connected to one side of said third socket, conductor means permanently connecting the other side of said first socket to one side of said second socket, conductor means permanently connecting the other side of socket to permanently connect said first, second and third sockets in series with said line wires, manually'operated means for temporarily connecting said outlet sockets in parallel with said line wires comprising a double pole switch, means connecting one side of said switch between said one line wire and the conductor means between said third and said second outlet sockets, and means connecting the other side of said switch between said other line wire and the conductor means between said first outlet socket and said second outlet socket, and a second manually operated switch connected between the two sides of said second outlet socket whereby, with said second switch closed, said first and said third outlet sockets can be energized without energizing said second outlet socket.

3. A photographic illumination system comprising a first, a second and a third outlet socket, a two wire power line having one wire permanently connectedto one side of said first socket and its other wire permanently connected to one side 01' said third socket, conductor means permanently connecting the other side of said first said third socket to the other side of said second 1 iii socket to one side of said second socket, conductor means permanently connecting the other side of said third socket to the other side of said second socket to permanently connect said first, second and third sockets in series with said line wires, manually operated means for temporarily connecting said outlet sockets in parallel to said line wires comprising a switch having two opposed pair of contacts, a pair of switch arms, means resiliently holding said switch arms in electrically conductive engagement with respective contacts of one of said opposed pair of contacts, manually operated means connected to said switch arms for moving said switch arms away from said one pair of contacts and into electrically conductive engagement with respective contacts of the other pair of contacts, means connecting one contact of said other pair with said one line wire and the respective switch arm to the conductor means between said third and second outlet sockets, means connecting the other contact of said other pair of contacts to said other line wire and the respective switch arm to the conductor means between said first and second outlet sockets for connecting each of said outlet sockets directly between said line wires when said switch arms are manually closed with said other pair of contacts, anda manually operated switch connected between the two contacts of said one pair of contacts and operative when closed to establish a shunt circuit around said second outlet socket.

BENJAMIN C. ANDERSON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Certificate of Correction Patent No. 2,486,?27 November 1, 1949 BENJAMIN O. ANDERSON It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows:

Column 5, line 13, after the Word socket and before the period insert and said second outlet socket; and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Ofiice. Signed and sealed this 21st day of February, A. D. 1950.

THOMAS F. MURPHY,

Assistant Commissioner of Patents.

Certificate of Correction Patent No. 2,486,727 November 1, 1949 BENJAMIN C. ANDERSON It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows:

Column 5, line 13, after the word socket and before the period insert and said second outlet socket; v and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Ofiice. Signed and sealed this 21st day of February, A. D. 1950.

THOMAS F. MURPHY,

Assistant Commissioner of Patents. 

